<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        let temp
        function Person(){
            this.name = name
            this.age = 20
            // temp = this
        }
        Person.prototype.fn = function(){
            console.log("fn")
            temp = this
        }
        console.log(Person.prototype.constructor === Person)
        let zhangsan = new Person('张三')
        zhangsan.fn()
        console.log(zhangsan===temp) //true
    </script>
</body>
</html>